<Collapse DefaultActiveKey="@(new[]{"1"})" Accordion>
    <Panel Header="This is panel header 1" Key="1">
        <p>@text</p>
    </Panel>
    <Panel Header="This is panel header 2" Key="2">
        <p>@text</p>
    </Panel>
    <Panel Header="This is panel header 3" Key="3">
        <p>@text</p>
    </Panel>
</Collapse>

@code{

    string text = @"
A dog is a type of domesticated animal.
Known for its loyalty and faithfulness,
it can be found as a welcome guest in many households across the world.
";

}